Devices and methods for synchronized signaling of the positions of moving pedestrians or vehicles

ABSTRACT

Position indicating devices, systems and methods useable for signaling the positions of pedestrians or vehicles.

RELATED APPLICATION

This application is a continuation of copending U.S. patent applicationSer. No. 16/848,529 entitled Devices and Methods for SynchronizedSignaling of the Positions of Moving Pedestrians or Vehicles filed Apr.14, 2020 and issuing on May 18, 2021 as U.S. Pat. No. 11,013,091, whichis a continuation of U.S. patent application Ser. No. 16/029,379entitled Devices and Methods for Synchronized Signaling of the Positionsof Moving Pedestrians or Vehicles filed on Jul. 6, 2018 and issued onMay 19, 2020 as U.S. Pat. No. 10,660,183, which claims priority to U.S.Provisional Patent Application No. 62/529,423 entitled SynchronizedBehavior of Bicycle, Motorcycle, and Pedestrian Warning Devices filed onJul. 6, 2017, the entire disclosure of each such application beingexpressly incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to the fields of electronics andtraffic engineering and more particularly to systems and methods fortransmitting visibility-enhancing or warning signals from group(s) ofmoving pedestrians or vehicles.

BACKGROUND

Pursuant to 37 CFR 1.71(e), this patent document contains material whichis subject to copyright protection and the owner of this patent documentreserves all copyright rights whatsoever.

Pedestrians (e.g., runners, joggers, walkers, etc.) and occupants ofcertain vehicles (e.g., bicyclists, motorcyclists, drivers ofslower-moving or otherwise vulnerable vehicles) can be susceptible toinjury due to vehicular impact. Such pedestrians and vehicles sometimestravel or move along a roadway in groups of two or more. For example, apeloton of bicyclists might include 20 to 50 or more riders. When spreadout in the direction of travel in the early morning or evening, frontand/or rear lights attached to the bicycles may flash to provide warningto approaching drivers of motor vehicles. However, to the approachingvehicle driver, this may appear from a distance as random flashinglights without giving the oncoming driver a clear appreciation of theoverall size of the group.

Existing warning lamps installed on bicycles, motorcycles and othermoving vehicles flash to warn approaching drivers. The individual flashof either a forward or rear facing lamp has limited energy and,therefore, limited visual light output owing to available power andreflector surface area. Improvements in efficiency (LED versusincandescent) of the light source, sophisticated optic, and improvedbattery technology have led to better warning lights. However, injury asa result of impact continues and with increasing frequency. There is aneed for improvements in warning light optics, power, and efficiency.Pedestrians suffer the same disadvantage when walking along a roadside.Groups of children walking to school, for example, in the early morninghours of winter are difficult to see in the darkness. Flashing lamps onthe backpacks, headgear, shoes or garments worn by such pedestrians canmake them more visible to oncoming drivers.

In accordance with this invention, such flashing lamps may flash insynchrony or unison or otherwise emit light in synchrony or unison(e.g., solid non flashing, pattern-flashing, etc.) when severalpedestrians or vehicles are moving in a group, thereby enhancing theperceived brightness and size of the emitted light and rendering thegroup more visible to oncoming traffic.

SUMMARY

In accordance with one aspect of the present disclosure, there areprovided position indicating devices which emit synchronized positionindicating signals when moving within a particular distance range (i.e.,a synchronization range) of other ones of such moving devices. In someembodiments, these devices may be in the form of electronic flares whichemit flashes of light or other signals, examples of such flares beingdescribed in U.S. Pat. Nos. 7,088,222; 7,106,179; 8,154,424; 8,550,653;8,564,456; 8,579,460; 9,288,088; 9,835,319; D510,289; D515,957;D515,958; D560,533; D654,387; D669,805; D778,752 and D778,753 as well asUnited States Patent Application Publication Nos. 2013/0113634;2016/0186971 and pending U.S. patent application Ser. No. 15/893,420,the entire disclosure of each such patent and application beingexpressly incorporated herein by reference. In some embodiments, thesedevices may be attached to or integrated/manufactured on or in avehicle, vehicle accessory or other object, such as, for example,vehicles, bicycles, bicycle seats, bicycle lamps, motorcycles,motorbikes, wearable garments, vests, shoes, running shoes, headgear,caps, hats, helmets, hard hats, straps, leg straps, arm straps, belts,back-packs, lanyards, jewelry, ear rings, necklaces and wrist bands.

In accordance with another aspect of the present disclosure, there areprovided position indicating devices which are operable while movingalong with other such devices, wherein each such device comprises: atleast one emitter which emits a position indicating signal; a radio orother receiver (which may include a transmitter as well); a powersource; and electronic circuitry configured and programmed to a) receivesynchronization signal(s), via the receiver, from other positionindicating devices located within a synchronization range of saiddevice; and b) in response to the receipt of one or more synchronizationsignal(s) from one or more other position indicating devices locatedwithin the synchronization range, causing said at least one emitter toemit a signal that is synchronized with signals being emitted by saidone or more other position indicating devices located within thesynchronization range.

In In accordance with another aspect of the present disclosure, there isprovided a method for using a plurality of position indicating devicesto indicate the positions of a plurality of moving pedestrians orvehicles, said method comprising the step of causing each of saidpedestrians or vehicles to be equipped with at least one of saiddevices, each of said devices comprising an emitter which emits positionindicating signals and control apparatus programmed to i) sense whenthat device is within a synchronization range of one or more of theother devices and, when within said synchronization distance range ofone or more others of said devices and, ii) cause that device's emitterto emit a position indicating signal that is synchronized with positionindicating signals being emitted by said one or more of the others ofsaid devices that are positioned within the synchronization range.

Further aspects and details of the present invention will be understoodupon reading of the detailed description and examples set forthherebelow.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description and examples are provided for thepurpose of non-exhaustively describing some, but not necessarily all,examples or embodiments of the invention, and shall not limit the scopeof the invention in any way.

FIG. 1 is a diagram showing the elements of one embodiment of positionindicating device of the present invention.

FIG. 2 is a diagram of one embodiment of a system of the presentinvention comprising a plurality of position indication devices as shownin FIG. 1, attached to or carried by pedestrians or vehicles movingalong a roadway or other thoroughfare.

FIG. 3 is a diagram showing one non-limiting example of an operatingprotocol by which position indicating devices of the present inventionmay be programmed to operate.

FIG. 4 is a diagram showing a protocol by which position indicatingdevices of the present invention may be programmed to distinguishbetween separate groups of pedestrians or vehicles which pass or comenear each other.

FIG. 5 is a diagram showing one non-limiting example of a mesh networkor “master-slave” network which may be used in devices of the presentinvention.

DETAILED DESCRIPTION

The following detailed description and the accompanying drawings towhich it refers are intended to describe some, but not necessarily all,examples or embodiments of the invention. The described embodiments areto be considered in all respects only as illustrative and notrestrictive. The contents of this detailed description and theaccompanying drawings do not limit the scope of the invention in anyway.

When several bicyclists are riding along the side of a road, theirwarning lamps may blend in with ambient and infrastructure lamps placedfor multiple purposes. For example, light emanating from store fronts,crossing automobiles, retail buildings, etc., all will tend to obscurethe flashing warning lamp of the bicyclist. Also, when vehicles attemptto travel in a group, such as a funeral procession, military vehicleconvoy, etc., it is sometimes difficult for other vehicles traveling onthe same roadway to visually perceive the existence or extent of suchgroup. The present invention provides signaling devices and systemswhich may be embodied in, held, carried, worn or affixed to suchpedestrians or vehicles and are programmed to emit synchronized positionindicating signals when such pedestrians or vehicles ate moving in agroup, thereby aiding visibility and perception of the group.

In another non-limiting example, the present invention provides means toenhance or multiply the safety features of bicycle or motorcycleillumination. The multiplication factor is simply the number ofbicyclists in the group (peloton). Currently, each flashing lamp whennot coordinated with the light output of other members of the groupprovides a fraction of the group's total available battery energy andlight output. By providing coordination of the individual flashing lampsthe “group” will appear as a much larger and brighter entity, therebyproviding safety beyond that available to multiple,independently-flashing bicycles warning lamps.

This invention addresses the advantage provided by coordinating a largenumber of individual flashing safety lights on a group of moving nodes(for example, bicycles, motorcycles, motor homes, road-side walkers orjoggers, etc.). By coordinating the flashing of LED lamps on individualnodes, the “Group” is made to appear larger and more distinctive,thereby providing a safety advantage.

Using radio, infrared, or sound communication, a mesh-network,master-slave, or hybrid communications network, the formerly independentflashing of lamps on moving and non-connected vehicles or pedestrianscan be coordinated such that all the lamps flash in unison, or insequence, or in some other more readily visible pattern.

This invention addresses the challenges associated with coordinating anaction (for example, flashing of a lamp) amongst multiple, disparatemoving entities. To provide for dynamic position synchrony, the networkmust account for positional changes as well as signal strengthvariations owing to multipath reflection off automobiles, trucks, andbicycles. In addition, simultaneous flashing of all the lamps requiresnetwork coordination, timing, and the ability for dynamic numbering ofnetwork nodes leaving and joining the network.

FIG. 1 shows an example of basic elements that may be included in aposition indicating device 12 of the present invention. FIG. 2 shows anexample of a system (e.g., a network or group) comprising a plurality ofposition indicating devices 12 a through 12 f (e.g., each devicerepresenting a separate “node”) moving in a common direction along aroadway or other thoroughfare RW.

As seen in FIG. 1, each device 12 comprises at least one emitter 16(such as an LED, other light source, speaker, horn, etc.) which emits aposition indicating signal, a radio or other receiver 14 (which may insome embodiments also comprise a transmitter), a power source 20 (e.g.,a battery or solar panel) and electronic circuitry 18 (e.g., anintegrated circuit having a controller). The electronic circuitry 18 isconfigured and programmed to receive synchronization signal(s), via thereceiver 14, from other such position indicating devices 12 locatedwithin a synchronization range SR of the present device 12 and, inresponse to the receipt of one or more synchronization signal(s) fromone or more other position indicating devices 12 located within thesynchronization range SR, causing the emitter(s) 16 to emit a signalthat is synchronized with signals being emitted by said one or moreother position indicating devices 12 a through 12 f located within thesynchronization range SR.

In the example shown in FIG. 2, four of the six devices 12 b, 12 c, 12 dand 12 e are within synchronization range SR of one another. Thus,devices 12 b, 12 c, 12 d and 12 e are all emitting a synchronizedposition indicating signal. However, non-grouped devices 12 a and 12 fare currently outside of the synchronization range SR of all of theother devices in the network or group and, therefore, devices 12 a and12 f are either not emitting any signal, or are emitting signals whichdiffer from or are not synchronous with the signals being emitted by thegrouped devices 12 b, 12 c, 12 d and 12 e.

If one of the non-grouped devices 12 a or 12 f subsequently becomeswithin the synchronization range SR of any of the grouped devices 12 b,12 c, 12 d or 12 e, that device will then automatically join the groupand will adopt/begin to emit the synchronized position indicating signalalong with the other grouped devices 12 b, 12 c, 12 d and 12 e.

If one of the grouped devices 12 a, 12 b, 12 c, 12 d moves outside ofthe group's synchronization range SR, that device will then then ceaseto emit the synchronized group position indicating signal and willeither become quiescent and not emit any signal or will adopt and beginto emit a different or non-synchronized position indicating signal.

In some embodiments, the synchronized group position indicating signalemitted by the grouped devices 12 b, 12 c, 12 d and 12 e may besequential in nature. For example, flashes of light may be emitted insequential order from the first device 12 b to the last device 12 d orfrom the last device 12 d to the first device 12 a. In such sequentialembodiments, if the order of the grouped devices 12 b, 12 c, 12 d, 12 echanges, the devices will be programmed to automatically re-sequencethemselves to maintain the desired first-to-last or last-to-firstsequence, even though the actual order of the devices within the grouphas changed change.

Mesh-Network

When multiple bicycles or pedestrians or other vehicles utilizing thesame equipment approach each other and are within radio range, one ofthe radios must assume control to initiate the coordinating signal.However, this same temporary master may soon move out of range. Hence,any other node (bicycle) must be capable of assuming control.Furthermore, as all the devices are programmed exactly the same, thereis no predefined “master” or “slave”. The network must be able todynamically hand off control from each member to the next. Hence, thenetwork must act both as a master-slave and as a mesh depending uponrange and conflict issues. A novel aspect of this invention is thedynamic shifting between mesh and Master-Slave topologies. A fundamentalaspect of this is that all nodes when not within range of another nodewill, for example, flash the lamp once-per-second. However, two nodesmay not be flashing in synchrony even though each is flashing atonce-per-second. Once in range, each node will establish the “master”clock to synchronize the emitted signals (e.g., flashes of light).

With reference to FIG. 3, one example of an operating scenario is thattwo nodes approach within range. Each node randomly or coordinated withthe LED flash transmits a signal requesting control of the network(Request-Control Signal—RCS) and seeks an acknowledgement. The firstnode to transmit the request-control signal will take control of thenetwork. Upon receipt of the Request-Control Signal, the second nodewill a) acknowledge receipt of the signal and b) cease sending outRequests Control Signals and simply go into receive and propagate mode(mesh-network). The second of the two nodes will flash according toinstructions and timing from the first (Master-Slave). Both nodes willbegin to send out a Network-Established Signal (NES) that is coordinatedwith the LED flash. The Network-Established Signal will include flashcharacteristics (time, duration, frequency, etc.) and number of nodes inthe network. As additional members of the group move into range, theytoo will be sending randomly-timed Request-Control Signals. However, thefirst two nodes, having already established a network, will not respondbut will continue to flash and send out Network-Established Signals thatincludes number of nodes in the network. If a single new node moveswithin range it will receive a Network-Established Signal with networksize=2. This Network-Establish Signal will elicit an acknowledgementthat will increase the size of the network to 3 nodes. This parameter,network size, will continue to be propagated to all nodes in the network(mesh-network).

Should a similar series of events occur in an approaching group ofcyclists where a network has already been established, then a potentialconflict will occur. Both groups, having formed networks independently,will be transmitting Network-Establish Signals. However, one of theparameters is network size. The network with the greater number ofnodes, for example (could be smaller node count takes control) will takecontrol of the smaller network. The smaller network will continuetransmitting Network-Establish Signals but with a) a new node numberthat includes the sum of both groups; b) adopt the NES identifier of thelarger group; and c) in unison with the larger group.

Merging of Networks

Referring to FIG. 4, a group of nodes (bicyclists, for example) havingformed a network (group) may now come upon another group of nodes alsooperating as a group. When a device in Group-1 receives a NetworkEstablished Signal (NES) from Group-2, the member will compare the nodecount transmitted by Group-2 with that transmitted from within its ownGroup-1. (The same is taking place with the Group-2 member). If thenode-count of Group-2 is larger, the Group-2 member first receiving theGroup-1NES will transmit a Network-in-Charge (NIC) signal with theGroup-2 identifier. This signal will be relayed by any node, eitherGroup-1 or Group-2, to other nodes that might not be in range of theinitiating Group-1 member (mesh-network). The NIC signal takesprecedence over other commands. Once a member of Groups-1 or -2 receivethe NIC signal, they will all begin transmitting a Network EstablishedSignal (NES) with Group-2 identifier and with the new Node-Count (sum ofGroup-1 and Group-2).

As other Groups approach, the same systematic approach to establishing asingle Group will take place. Should groups have the same number ofnodes, the tie-breaker will be the unique identifier of each node(similar to MAC address). The node with the lower numeric uniqueidentifier will take control. In another embodiment, the higher numericidentifier might take control.

Simultaneous Flashing of Nodes

In systems of the present invention, a mesh network or “Master-Slave”network may be used to coordinate timing. Other modalities include GPStiming signals received via satellite, real-time clock modules, orcellular timing signals or timing signals from Universal TimeTransmission (e.g. WWV Fort Collins, Colo. or similar government timingbroadcast in Europe or Asia). The technical approach used includesestablishing a common clock signal across the network. To simultaneouslyflash all lamps in the network, the new approach described in thisdocument incorporates a fixed delay between sequence number in thenetwork and the flash of the lamp. For example, using a 10-lamp network,node number 1 sends a signal to its most immediate neighbors defining atiming signal. It then waits 900 milliseconds to flash its lamp. Nodenumber 2 hears the signal and waits 800 milliseconds to flash its lamp.Node number 3 hears the signal and waits 700 milliseconds to flash itslamp. This continues until lamp number 10 receives a clock signal andflashes immediately. The lowered number lamps all are staged to flash atthe same time even without direct radio, infrared, ultrasound, or othermedia communication. Based upon this scheme, all 10 lamps will flashsimultaneously. If 11 lamps are in the system, then node 11 will hearthe signal from node 10 other nodes and delay its flash for 900milliseconds. It will flash at the same time as node 1, which is thesame as all the other nodes.

The net effect is that despite being out of range of all but one lamp,all the lamps will flash simultaneously; each lamp need not “hear” lampnumber 1, or any other number lamp. Using an “association matrix” orneighbor table, each lamp must hear only 1 of the closest 8 lamps; thatis, any one of 4 lamps with numbers greater than N or 4 lamps withnumbers lower than N.

This is illustrated in Table 1 below:

TABLE 1 Association Table a) ◯ ◯ ◯ ◯ N ◯ ◯ ◯ ◯ b) 1 ◯ 1 1 N 1 ◯ ◯ ◯

In the above Association Matrix illustrated by line b) above, lamp Nreceives information from 3 lamps with lower sequence number and 1 lampwith higher sequence number. Any one of these lamps can provide thenecessary information for lamp N to acquire timing and flash-delay data.Hence, lamp N need not be in range of lamp 1.

To dynamically establishing relative positioning, an “associationmatrix” or neighbor table is used to efficiently define the absence orpresence of neighboring nodes.

Sequential Flashing

An alternative to multiple moving nodes (bicycles, vehicles,pedestrians) flashing lamps in unison is for the lamps to flash in asequential order from last-in-line to first-in-line. This flash patternwill present a dynamic flashing “arrow” to approaching motorists. Toaccomplish this, each node must establish its physical location(position) relative to the other nodes. Furthermore, as one bicyclepasses another, this position must change dynamically to renumber thenodes.

An alternative algorithm could use the combination of tail-lamp andhead-lamp to communicate sequence number from trailing to leading nodes(bicycles, for example). Linking the tail-lamp and head-lamp would allowfor a modulated signal to carry position and sequence information in thevisible light spectrum, infrared spectrum, using high-frequency sound,or radio communication. The tail-lamp and head-lamp of any one bicycleor other vehicle or pedestrian would communicate with each other viaradio (Bluetooth, Wi-Fi, for example), hard wire connection, sound,infrared light, etc. The node number would therefore be transmitted byvisible light modulation or infrared-light modulation or sound or radioto the physically closest leading node and physically closest followingnode. The rear-most tail lamp would not receive a recognized signal frombehind, and therefore, would assume the sequence position at the end ofthe peloton. The head-lamp would send position information to the nextbicycle in line. This information would be received by the tail lampahead (using a photodetector, phototransistor, photodiode, LED acting asa photodiode when not flashing, etc.). The next member would continue tosend its position information to the node ahead, and so on. Thisarchitecture would allow for rapid sequencing of multiple lamps. Asmoving nodes (pedestrians, bicyclists, vehicles) changed position, thenew physical location would be established via node number transmittedand received from the tail-lamp and head-lamp.

Master-Slave

Alternatively, and depending upon size of the plastic enclosure of thelamp and length of antenna, a lower frequency (greater range) radiosignal may be used. This will allow for deployment of a simple“Master-Slave” system where one node (bicycle) is designated as theMaster, and all other nodes are “Slaves”. At lower frequencies, therange of the Master will be adequate to control all Slaves within a 2kilometer or greater range.

Dynamic Flashing Pattern

Once the individual nodes are “linked” by the mesh-network,Master-Slave, or Hybrid network, the rate of LED flash and pattern maybe dynamically controlled. For example, with proximity detection usingultrasound, radar, laser reflection, head-light intensity, etc., avehicle approaching from the rear of the group could be sensed andthrough microcontroller firmware embedded in the flashing lamp changethe flash pattern. Changes could include longer duration duty cycle offlash, brighter flash, more rapid flash, etc. This would alert theapproaching driver by providing dynamic patterns rather than amonotonous constant flashing pattern. For example, as the vehicleapproaches, the simultaneous flashing of many bicycle tail lamps canincrease in brightness and rapidity of flashing and ultimately become a“constant-on” or steady-burn illumination to make the bicyclists mostvisible. Alternatively, the color of the flashing tail-lamps couldchange from amber to red, or green, based upon proximity of anapproaching vehicle. This dynamic response of the flash pattern to theapproaching vehicle represents a novel and important safety feature.

Crowd Synchronized Behavior

Large groups of pedestrians (crowds) wearing devices that emit light orsound or other energy form can be coordinated in a similar fashion.Recent demonstrations of this crowd dynamic behavior have been seen inOlympic stadiums, where wrist bands or head lamps will flash withdifferent color and patterns. In all the demonstrations, however, thecoordinating signal is infrastructure dependent, that is, an infrared orradio signal is broadcast from a central location in close proximity tothe crowd, and often in line-of-sight of the crowd. The “master” signalmay be broadcast by several infrared light sources that are hard-wiredto a central control system. In the proposed invention, coordination ofcrowd node behavior does not require a central infrastructure source ormaster signal. The control signal can be generated by any node andimmediately control the behavior of all nodes in the network. Forexample, in a large football stadium with 100,000 fans, each carrying alow-cost node, a change of the electronic behavior of each node (LEDcolor, flash rate, intensity, sound emission, etc.) can be coordinatedby any single node in the crowd, if programmatically permitted, or by anadministrator node sitting in the crowd. The same crowd can exit thestadium and synchronized, coordinated behavior would continue. There isno need for a high-energy, centrally located infrared or radio signal tobe in line-of-sight of all the nodes.

Group Behavior Versus Individual Behavior

With successful linking of two or more bicycles, motorcycles, vehicles,pedestrians, etc. (nodes), the flash dynamics could be designed tochange. For example, while solo riding, a bicycle taillight might flashfor 100 milliseconds once per second. However, when “linked” to anotherbicycle via radio, infrared, light, or other signaling modality, thetaillight might cease flashing and initiated a “Steady Burn” mode whereboth lamps (two bicycles) stays lit continuously. In a large group,simultaneous flashing might be annoying or less effective than steadyillumination of the group. The group can choose one of many “patterns”that will become “default” once a group is formed, and this can bedifferent than the flash pattern when an individual is riding solo. Thelamp will have a solo mode and group mode, both programmable by theoperator.

Although the invention is described with respect to pedestrians orvehicles which are “moving,” it is to be appreciated that in someinstances the movement of some or all of the pedestrians or vehicles maystop. For example, a group of pedestrians or cyclists traveling along aroadway may stop from time to time, and then subsequently resumemovement. In some instances, the position indicating devices may remainon and may continue to emit their position indicating signals while thepedestrians or vehicles are stopped. In other instances, the positionindicating devices may be turned off while the pedestrians or vehiclesare stopped and may then be re-started when the pedestrians or vehiclessubsequently resume movement. Also, the reference to moving pedestriansherein shall be construed to include not only pedestrians who arewalking, jogging, standing or running but also persons who areperforming actions or otherwise moving about within an area, such asworkers or emergency personnel who are working in a construction zone oraccident site on or near a roadway or other thoroughfare.

It is to be appreciated that, although the invention has been describedhereabove with reference to certain examples or embodiments of theinvention, various additions, deletions, alterations and modificationsmay be made to those described examples and embodiments withoutdeparting from the intended spirit and scope of the invention. Forexample, any elements, steps, members, components, compositions,reactants, parts or portions of one embodiment or example may beincorporated into or used with another embodiment or example, unlessotherwise specified or unless doing so would render that embodiment orexample unsuitable for its intended use. Also, where the steps of amethod or process have been described or listed in a particular order,the order of such steps may be changed unless otherwise specified orunless doing so would render the method or process unsuitable for itsintended purpose. Additionally, the elements, steps, members,components, compositions, reactants, parts or portions of any inventionor example described herein may optionally exist or be utilized in theabsence or substantial absence of any other element, step, member,component, composition, reactant, part or portion unless otherwisenoted. All reasonable additions, deletions, modifications andalterations are to be considered equivalents of the described examplesand embodiments and are to be included within the scope of the followingclaims.

1-47. (canceled)
 48. A wearable signal emitting device comprising: awearable article comprising a wearable garment, vest, shoe, runningshoe, headgear, cap, hat, helmet, hard hat, strap, leg strap, arm strap,belt, back-pack, lanyard, jewelry, ear ring, necklace or wrist band; anda position indicating device attached to or integrated in the wearablearticle; wherein the position indicating device comprises at least oneemitter which emits a position indicating signal; a receiver; a powersource; and electronic circuitry; and wherein input signal(s) arereceived via the receiver and the electronic circuitry causes theposition-indicating signals emitted by the emitter to change in responseto the receipt of one or more input signal(s).
 49. A device according toclaim 48 wherein said at least one emitter emits a position indicatingsignal that is directional, omni-directional, or quasi-directional. 50.A device according to claim 48 wherein said at least one emitter emits aposition indicating signal that comprises electromagnetic radiation. 51.A device according to claim 50 wherein the electromagnetic radiation isselected from: visible, invisible, infrared, ultraviolet, microwave, orradio frequency radiation.
 52. A device according to claim 48 furthercomprising global positioning system (GPS) receiver.
 53. A deviceaccording to claim 52 wherein the GPS receiver receives a radio clocksignal transmitted by government or standards agency and wherein theelectronic circuitry is configured to determine its current positionbased on said radio clock signal.
 54. A device according to claim 52further comprising a transmitter for transmitting its current position.55. A device according to claim 54 wherein the transmitter transmits thedevice's current position such that its current position is indicated ona GPS display or other mapping system.
 56. A device according to claim48 further configured to sense proximity of an oncoming vehicle and tocause the position indicating signal to change in response to the sensedproximity of the oncoming vehicle.
 57. A device according to claim 56wherein proximity of an oncoming vehicle is sensed by ultrasound, radar,laser reflection or head-light intensity.
 58. A device according toclaim 56 wherein the emitter emits visible light which increases inintensity, changes in intensity or changes in color in response tosensed proximity of an oncoming vehicle.
 59. A device according to claim58 wherein the emitter emits flashes of light which become more rapid orbecome continuous in response to sensed proximity of an oncomingvehicle.
 60. A device according to claim 48 configured to transmit asynchronization signal to other devices located within a synchronizationrange of that device.
 61. A device according to claim 60 wherein thesynchronization signal transmitter is of a type selected from:radiofrequency transmitters, Bluetooth transmitters, WiFi transmitters,electrical hard wire connections, visible light transmitters, infra-redlight transmitters, light pulse transmitters, LiDAR devices, soundtransmitters, speakers, percussion emitters, ultrasound transmitters,radar devices, short range radar (SRR) devices, medium range radar (MRR)devices, long range radar (LRR) devices, moving apparatus detectable bymotion sensors or motion detectors and transmitters which transmitphotonic images detectable by cameras.
 62. A system comprising aplurality of devices according to claim 60 wherein the electroniccircuitry of each device uses received synchronization signals to causeits signal emitter to emit position indicating signals which aresynchronized with those emitted by others of said devices located withinsaid synchronization range.
 63. A system according to claim 62 whereinthe devices operate as a mesh network when within said synchronizationrange.
 64. A system according to claim 62 wherein each device begins toemit synchronized position indicating signals when it moves into saidsynchronization range and ceases to emit synchronized positionindicating signals when it moves out of said synchronization range. 65.A system according to claim 64 wherein a device that moves out of saidsynchronization range either stops emitting any positioning signal orbegins to emit non-synchronized position indicating signal.
 66. A systemaccording to claim 62 wherein the signal emitters of devices locatedwithin said synchronization range emit flashes of light in asynchronized format selected from: flashes of light in sequenceprogressing from a first-positioned device to a last-positioned device;flashes of light in sequence progressing from a last-positioned deviceto a first-positioned device; flashes of light in unison; continuouslight in unison; flashes of light in predetermined flashing pattern;flashes of light in predetermined color pattern; and concurrent flashesof light from pairs of said devices within said synchronization range.67. A system according to claim 62 wherein each device comprises: anantenna configured to receive and transmit a radio frequency (RF) signalor photodetectors and transmitters to provide visible or infrared lightmodulated communication, computer hardware comprising a microcontrollerconfigured to perform instruction stored in memory, a RF transceiver orphotodetectors configured to transmit and receive messages from themicrocontroller, and a power source; and memory comprising a neighbortable including a timing indicator of neighbor modules, the timingindicator indicating a latency before emitting the warning signal withrespect to a network-coordinated clock; wherein the computer hardware isconfigured to share timing and a relative position data to at leastmodules in its neighbor table, the relative position at least in partbased on the proximity indicator, the timing and relative position dataused to synchronize simultaneous emission of the warning signal with atleast the modules in its neighbor table.
 68. A system according to claim62 wherein the devices emit position indicating signals of a typeselected from: visible or infrared light, constant visible or infraredlight, blinking, flashing or intermittent visible or infrared light, aparticular pattern of blinking, flashing or intermittent visible orinfrared light, light of changing colors, sound, constant sound,intermittent sound, a particular pattern of intermittent sound and soundof changing volume, pitch, type or character.